Last week we started looking at the many structures and textures of igneous
rocks and ... Petrology involves a lot terminology and I want to take this week to ...
Petrology Lab #3 Last week we started looking at the many structures and textures of igneous rocks and familiarizing ourselves with some of the terms we will need to know to describe these rocks. Petrology involves a lot terminology and I want to take this week to make sure we can use and understand the terms, read the tables and figures, and begin recognizing mineral compositions. We will start this week by reviewing the hand out from last week. Then we will go through this handout, page by page, and examine the figures and tables. There will be a quiz next week; all material covered today is fair game. All figures are taken from Igneous and Metamorphic Petrology; Myron G. Best, 2003.
Chart to aid the visual estimation of modal proportions of minerals in rocks.
Classification chart for plutonic igneous rocks with 0-90% mafic minerals. (Intrusive) You should be familiar with the descriptive rock names and their relative locations.
Classification chart for volcanic rocks with 0-90% mafic minerals. (Extrusive) You should be familiar with the descriptive rock names and their relative locations.
Classification of aphanitic and glassy volcanic rock types. (fig 2.12)
Radii and classification of positively charged ions of major and trace elements. Compare this to the next table that shows what elements commonly substitute in for others.
Table 2.4
Trace Elements Substituting for Major Elements of Similar Ionic Size and Charge (see Figure 2.20) .Major Element
Substituting Trace Element(s)
Si
Ge. P
Ti
V
Al Fe Mg Ca Na K
Ga Cr, Co, Ni Cr, Co, Ni Sr, Eu, REE’s Eu Rb, Ba, Sr, Eu
Percent Composition Triangle
What can trace element compositions tell us about the petrogenesis of a rock (how it was formed)?
Abbreviations for common rock-forming minerals and their formulas.
